The colon measures about 5 feet (1.5 meters) in length. It goes up (the ascending colon) on the right side of the abdomen, across the abdomen (the transverse colon) beneath the stomach, and then down (the descending colon) on the left side of the abdomen and makes a sharp turn in the left lower portion (the sigmoid colon) to merge with the rectum.
The colon is sometimes inaccurately called the "large intestine" or "large bowel". It is only a part of the large intestine/bowel. The confusion may have arisen because the word colon came from kolon which to the ancient Greeks meant the "large intestine".
Some nutrients and drugs are absorbed by the lower bowel. In humans, cellulose is not digested or absorbed but passes from the body as unchanged residue.
Although IBS can cause chronic recurrent discomfort, it does not lead to any serious organ problems.
Making the diagnosis usually involves excluding other illnesses. Treatment is directed toward relief of symptoms and includes changes in diet (eating high fiber and avoiding caffeine, milk products and sweeteners), exercise, relaxation techniques, and medications.
2. The part of the colon that turns medially at the left iliac crest, between the descending colon and the rectum; shaped like the letter "S".
Dear Mr. Jones:

The colon by some is thought odd,
And no wonder:
Two periods make it,
One over,
One under.
The colon resemble the eyes of a beast:
A tiger,
A fox,
Or a tomcat at least —
Two eyes ever looking, two eyes open wide,
That belong to a creature that lies on its side.
Unable to point or to say, "over there,"
All the colon can do,
And it does it,
Is stare.
So here's a suggestion: go on, if you please,
To where it is looking, to see what it sees.